Tank truck rollover accidents require the attention of trained emergency response teams as well as police and fire personnel in order to safely handle such incidents. The objectives of the trained emergency response teams are to protect people, to minimize impact on environment and to contain and recover product. Methods are preferred for gaining entry to tank compartments and removing product which minimize the potential to spill additional product. Emphasis is placed on planned, careful action with strong attention to safety precautions, techniques, procedures and equipment.
Stabilizing the situation is the first job of the emergency response team in attending to a rolled-over tank truck, even before deciding on a specific product recovery method. A first task is to monitor the air for vapor content. If vapor concentrations approach unsafe levels, the area is cleared and foamed down until the atmosphere is safe to work in. Tank compartments are checked for leaks, and if a dome cover is leaking, an attempt is made to slow down or stop the leaking. Product from any leaking that cannot be stopped completely is collected in containers or diverted away from active work areas. Absorbent materials or earth or sand dams may be used to confine product to a limited area. Finally, bracing the overturned tanker is important since its weight will change during the pumpoff operation, and the tanker may shift causing further product spill.
With the situation stabilized, the emergency response team decides on the product recovery method best suited to the circumstances and confers with authorities. In many cases it will be desirable to employ a combination of methods to remove product safely. Grounding and bonding to prevent static electric sparks which could cause fire or explosion is a must when working with gasoline or other flammable liquids. The rolled vehicle is grounded through a rod with the cable connected to the trailer first and then to the rod. Additional grounding and bonding precedes any flow of product from one container to another. Pumpoff vehicle, down spouts, hose couplings, recovery pans and tubs are all grounded. The pumpoff vehicle or vacuum truck is brought up to the side of the overturned tanker and positioned uphill and upwind since its engine and exhaust system could be a source of ignition.
It frequently is necessary to remove product from tankers through a dome opening which would normally be at the top of the tank. If this is the case, there is a particular problem with spillage of fluid inasmuch as a dome cover is held in place by a lever which must be released and some connection made to the dome opening prior to recovery of product. In the past, spillage has been almost inevitable in this process, and the danger to environment and workmen removing product has been a substantial hazard. Accordingly, there is a need in the art for a technique whereby product may be removed from a dome cover of a rolled over tank without spillage and without resulting hazard to workmen.